1. Technical Field
This invention relates to an apparatus for coupling a drive shaft and an associated reduction gear set with an accessory shaft to be driven thereby, and, particularly, to an apparatus for use in a shaft mountable gear drive in which torque transmitted by a gear drive set is used to generate a force adapted to facilitate the installation and removal of the gear drive to and from the accessory shaft.
2. Background Art
In a gear reduction drive, a driving input shaft transmits power from a power source to a driven shaft through a number of intermeshed gears. Frequently, the gears are mounted within a housing or gearbox, with the a driving input shaft extending through the gearbox and engaging one of the gears, and with the driven shaft extending through the gearbox and engaging another of the gears.
In one type of generally known gear reduction drive, a driven accessory shaft is coupled with the reduction gears by a hollow output shaft journaled within the gearbox. The output shaft has a tapered axial passage for receiving one end of the accessory shaft, which is generally cylindrical. An annular tapered bushing holds the accessory shaft end in the tapered axial passage for synchronous rotation therewith. A retaining nut is threaded to the output shaft outboard of the bushing and is tightened with a wrench to apply an axial force for wedging the bushing between the cylindrical accessory shaft and the interiorly tapered output shaft.
Substantial axial force is required to achieve the necessary locking action of the tapered bushing on the driven accessory shaft. Consequently, the level of torque required to be applied to the retaining nut for generating the necessary axial force can exceed the capability of an individual using a wrench to tighten the nut, making the installation of the tapered bushing and output shaft difficult, if not impossible. Also, when removing the gear drive, the tight fit of the taper may require more force than can normally be applied by a person using a wrench on the nut.
This invention is directed to solving this problem by providing a system for automatically locking or unlocking the retaining nut in response to rotation of the output shaft using the torque multiplication of the gear drive ratio.